Are you sure about the "no hole"? ?I query
this for two reasons:
Firstly, the deck I have of blank ones has all the holes around the edge
pre-punched.
There were several makers of edge punch cards, all slightly different in format.
Secondly, how would you sort? ?If there are any cards
at all in the deck
with the hole filled, you can't sort in a single operation. ?You have to
drill down to the filled hole and split the deck; extract the filled-hole
cards; and repeat until you've got to the end.
Yes, not a useful a sort as the normal method of lifting the cards,
but still valid.
I like the idea of a second hole, further in. ?This
implements ternary
rather nicely: the states are no slot, shallow slot, deep slot.
That is true - I had not thought of that as trinary, but I suppose it
is. It seems that having multiple levels was more used for nested
searches.
--
Will